Elastic gearing.



K. ALQUIST.

ELASTIC GEARING.

APPLlcAnoN FILED MAY5.1915.

Patented 001. 26, 1915.

2 SHEETS-SHEET l.

FTCL F7432.

Inventor:

Kar-l .347m ist, b9 MAM K. ALQUIST.

ELASTIC GEARING.

APPLlcAnoN man MAY5.1915.

mmm

Patented Oat. 26, 1915.

2 SHEETS-SHEET Z.

83 Inventor:

Karl .JCIQLlis KARL ALQUIST, 0F SCHENECTADY, NEWYORK.

ELASTIC GEARING.

Specification of Letters Patent.

Patented ct. 26, 1915.

Application led May 5, 1915. Serial No. 26,148.

useful Improvements in Elastic Gearing, of.

which the following is a specification.

The present invention relates to elastic or flexible gearing; that is, gearing in which one or more of the gear elements is capable Vof axial deflectionto compensate for inequalities in tooth pressure.

It. relates particularly to such gearing wherein the elastic element or elements comprises or .comprise a plurality of elastic or flexible plates or laminations rigidly mounted on a shaft or support, there being a small clearance space between the plates near the lperiphery. i

The face 0f the gear is provided with helically cut teeth which are free to yield laterally by a slight amount under the pressure of the teeth of the coperating gear. This yielding of the gear teeth is due to the fact thatthe metal plates are elastic and also to the fact that each plate atits periphery is separated from the other by a small space. I have found that in running gears of this type there appears to be under certain conditions excessive pressures between the driving and the driven teeth which cannot be accounted for by the load carried or by the/y ordinary errors in adjustment or in the shape of the teeth. I have also observed that there is sometimes set up a relative axial swinging motion between the two gear wheels running in mesh, which seems to be' different from the small axial motion generally present in gears, the periodicity of which follows the revolutions of the gears. The periodicity of this swinging motion on the other hand appears to be independent of the speed of the gear wheels and is evidently a function of the yrespective rotating masses,

and the springcapaclty of theflexible disks, though, the two motions referred to being simultaneous, its detection is made somewhat difficult. It is a well known fact that spring supported masses moved at high speeds generally have a tendency tovibrate and to increase the amplitude of vibration until it is limited by Ysome resistance to the movement. A flexible gear may be considered as a similarcase, and, if so, there is' very little re'- sistance present to limit the movement, and in addition to increased wear there will be danger of the disks being subjected to very severe bending stresses which would cause the material in time to crystallize and break.

I have vdiscovered that by introducing a small resistance to axial motion of the gear wheels severe wear of the teeth will be stopped; z'. e., a certain load on the gears without such resistance -will wear the teeth rapidly while the same load after the resistance is introduced will cause no noticeable wear. This resistance may be applied in various ways. A convenient method and one which I nowvprefer comprises the use of a dash pot device which, on well known principles, offers yielding resistance to axial motion of the shafts and thus damps or prevents any such motions. This dash pot device may, for example, use oil from the lubricating system.

In the accompanying drawing Figure l is a plan view of a single reduction gearing embodying my invention. Fig.l 2 is an end view, and Fig. 3 a plan of a second form of gearing embodying my invention; Fig. 4 illustrates a third form which my invention may take; Figs. 5 and 6 illustrate another form of my invention, Fig. 5 being a sectional view and Fig. 6 a face'view of one of the parts shown in Fig. 5; Fig. 7l illustrates an embodiment of my invention in connection with double reduction gearing, one yside of the upper half of the gearucasing being removed; and Fig. 8 shows still another form which my invention may take.

Referring first to Fig. l, 10 indicates a shaft carrying the solid helical pinion 1l which meshes with the elastic or flexible wheel 12mounted on the shaft 13. 1l indilCates a bearing for the free end 15 of the shaft 15 will act as a plunger and the motion 'will be retarded by its 'pumping action on the oil. In this figure the dash-pot is shown as applied to the end of the shaft carrying the flexible element, but it is to be understood that my invention is not limited to this arrangement, as the dash-pot device may be each other.

applied to the other shaft member, or even to both of them, as, will appear more clearly hereinafter.

Referring now to Figs. 2 and 3, 18 indicates a helical pinion driving the gear 19 through the two elastic gears 20. The driven gear 19 is omitted from Fig. 3 in order to make the view clearer. Associated with each of the free ends of the shafts carrying the elastic gears 20'are dash pot devices 21, of the same structure as shown in connection with Fig. 1. The action of these dash pot devices is the same as that described in connection with Fig. 1. Such a dash pot is especially suitable for this type of gear as the pressures on the ends of the shafts balance eachother.Y v

In Fig. 4 is shown a special type of dash pot which, although applied to one end of the shaft, provides a more nearly balanced pressure than would result from the arrangement shown in Fig. l. The structure amounts in substance to a double acting dash pot. The end of the shaft 25 which may be a shaft carrying a flexible gear or another shaft has an extension 26 of reduced diameter carrying a collar 27. Between this collar and the shaft are arranged the pistons 28 and 29 which slide in the cylinder 30 which surrounds the extension 26 and is closed on the end by a cap 3l. The cylinder 30 has a central inwardly projecting annular member 32 in which slides the annular projections 33 and 34 carried by the pistons 28 and 29 respectivelv. Oil or other fluid under suitable pressure is fed through passage 35 and leaks through between the various surfaces so as to fill the clearance spaces 36 and 37 between the member 32 and the pistons 28 and 29 and hold them in'position against the collar 27 and the shoulder o n shaft 25 respectively. It also acts to lubricate the parts. If found deslrable a spring 38 may also be nrovidedbetween the pistons 28 and 29 in order to insure that they follow the movements of the shaft. The oil or other fluid which leaks out past the piston 28 drains off by way of passage 39. It will be understood that the pressure of the oil or other fluid in the clearance spaces 36 and 37 on the pistons 28 and 29 normally balance In case of axial movement,

v however, in ,either direction the oil will offer the required resistance to prevent or dampen such movements or vibratins.

In Figs. 5 and 6 I have illustrated another form of my invention which is somewhat simpler than the form shown in Fig. 4, but which, however, is practically balanced and double acting.- 40 indicates a shaft of an 'elastic gearing set over the end of which l is placed a cap 41 which is cored out to provide aclearance space 42 between them. As best shown in Fig. 6, this cap is also provided;- with a plurality of concentric annular grooves which communicate with each other. In the present instance, two grooves 43 and 44 are shown. The inner groove 43 communicates with the clearance space 42 through the passage 45, and it communicates with the groove 44 through the passage 46 which is diametrically opposite the passage 45. The groove 44 at a point diametrically opposite the passage 46 communicates .with a discharge passage 47 which may communicate with a suitable drain pipe. Oil from the bearing in which the shaft 40 runs leaks out and fills the clearance space 42 from which the oil may pass to the discharge passage 47 by way of the grooves 43 and 44. These grooves, as will be seen, offer a passage of considerable length between the clearance space 42 and the passage 47, although ordinarily the oil may pass freely through them. The pressure in the clearance space and on the end of the shaft will be small as the pressure head of the oil in the grooves is small. In case of axial movement on the part of the shaft 40, however, a pumping action will take place which, in view of the considerable length of the grooves, will offer resistance both as to the reversal of direction in flow, as well as to the frictional resistance of the grooves, which will act to dampen or prevent axial movements or vibrations of the shaft and connected gears. It will be understood that the dash pot device may be acting either on the shaft of the flexible gear or on the shaft of the pinion -.in mesh therewith and such devices ma also be applied to both members.

In Fig. I have shown my invention in connection with a gearing of the double reduction type and in which the dash pot effect is obtained in connection with one or more of the couplings. In this figure 50 indicates a high speed shaft driving the pinion 51 which in turn meshes with two ilexible gears. Only one of these flexible gears 52 is shown in the drawing. It will be understood that the other is below the pinion and within the lower portion 'of the casing. The arrangement in the lower portion of the casing is a duplicate of that illustrated in the upper portion of the casing so that a description and illustration of one is sullicient. The elastic gear 52 is carried by the shaft 53 which is supported in bearings 54 and 55 and has an extension 56 which passes y through a hollow shaft 57 supported in the bearing 55 and bearin 58. The shaft 57 carries the gear 59 which meshes `with the driven gear 60 which is carried by the shaft 61. 'Ilhe shaft extension 56 and the hollow shaft 57 are coupled together in the following manner: The hollow shaft 57 has an enlarged portion 62 which is counterbored and is provided with slots 63 into which extend the several projections or fingers 64 carried by the member 65 keyed. to the end of the extension 56. The slots 63 are of greater' depth in an axial direction than the axial length of the projections 64 so as to permit of slight axial motion of the shaft extension 56 relative to the hollow shaft 57. The shaft extension 56 has a close sliding fit at its ends with the bore of the hollow shaft of pipe 68, passages 69, 70 and l, clearance f space 72, between the shafts 56 and 57, and the passages 73, 74 and 75. It will be understood that the passages 70 and 71 are grooves extending partly or Wholly around the shaft 56. It will thus be seen that the member 65 forms in substance a piston able frictional resistance to flow in either direction.- rIhese parts, therefore, act after the manner of a dash pot to prevent or dampen any vibratory axial motions of the shaft 56 which carries the flexible gear 52. 76 is a cap or casinflr which fits over the end of the coupling. corresponding cap for the coupling in the lower portion of the casing is indicated at 77.

Referring now to Fig. 8 wherein I have shown still another form of my invention, 80

indicates the end of a gear shaft supported in the bearing 81 and having a collar or plate 82 on its free end which is somewhat larger in diameter than the shaft. This cllar or plate makes a sliding lit with a projecting portion 83 of the bearing 81 and cut in the' outer surface of the projecting portion 83 is a screw-threaded groove 84. In-

closing the end of the shaft and surround-l ing the portion 83so as to close the open sides of the groove 84 is a cap 85 suitably attached to a supporting member 86 by means of bolts 87. Between the cap and collar 82 is a clearance space 88, and between the collar and the bearing 81 is an annular space 88a. One end of the groove 84 communicates with the clearance space 88 at 89, while the other end communicates with the passage 90. The arrangementl shown in this figure operates after the manner of that shown in Figs. 5 and 6. It has, however, certain structural advantages in that it is cheaper and easier to build. The oil leakingthrough the ibearing fills the annular space 88, the clearance space 88 and the groove 84 passing out through the passage 90. Ordinarily this oil offers very llttle pressure on the end of the shaft, the pressures in the two spaces 88 and 88a tending to a great extent to balance each other. In case of axial movement of the shaft, however, a pumping action, as already explained in connection with other of. the embodiments of my invention, takes Aplace so as to prevent or dampen these movements or vibrations.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof; But I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by Vother means such as are within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. rllhe ,combination with elastic helical spur gearing, of means associated therewith for preventing or damping relative axial motion between the gear wheels in mesh.

' 2. The combination with elastic helical spur gearing, of a dash pot device associated therewith for preventing or damping relative axial motion between the gear wheels in mesh.-

3. rllhe combination with elastic helical gearing, comprising a driving element, a driven element, and intermediate elastic gear elements through which power is transmitted from the driving to the driven element, of dash pot devices of which the free ends of the shafts which carrythe elastic gear elements form a part for preventing or damping axial vibrations among the respective gear elements. y

4. The combination with elastic helical gearing, comprising a driving element, a driven element, and an intermediate elastic gear elementthrough which power is transmitted from the driving to the driven element, of means associated with the shaft carryingthe elastic element for preventing or damping axial vibratory motion.

5. 'Ihe combination with helical gearing Y comprising an elastic gear, of a dash pot device associated with an end of the shaft of rality of plates clamped together at their central portion and slightly spaced apart at their periphery to permit of axial yieldcomprising a shaft which carries an elastic' gear formed of a plurality of plates clamped together at their central portion and slightly spaced apart at their periphery to permit of axial yielding, of a cap lwhich fits over the end of said shaft and forms an inclosed Space, and means for supplying fluid under pressure to such space.

9. In helical gearing, the combination of a driving gear, a driven gear, one of said gears being elastic so as to yield axially undertooth pressure, shafts for said gears, a cap which its over a free end of one of the shafts which carry the gears and forms therewith an inclosed space, and a pipe for supplying fluid under pressure to such space.

l'31.0. The combination with elastic helical gearing comprising a driving gear, a drivenv "gear, and two intermedlatev elastic vgears comprising a shaft carrying an elastic gear, of a cap which fits over a free end of one of the shafts and forms an inclosed space, and means forming a passage of substantial length which communicates with said space and through which fluid may move toward or away from it.

12. In double reduction helical gearing, the combination of a driving gear, a driven gear, and two intermediate gears, at least one of which is elastic, mounted on separate shafts and through which power is transmitted from the driving to the driven gear, of a coupling for said shafts, and means associated with said coupling forming a dash pot device for preventing or damping axial vibratory motion.

13. In double reduction helical gearing, the combination of a driving gear, a driven gear, and two vintermediate gears, at least one of which is elastic, mounted on separate shafts and through which power is transmitted from the driving gear to the driven gear, of a sliding coupling for said shafts which permits of slight relative axial motion of the shafts, and means associated with said coupling forming a dash pot for damping or preventing axial vibratory motion.

In witness whereof, I have hereunto set my hand this 4th day of May 1915.

KARL ALQUIST. 

